Question

If you were to create a phylogenic tree of these organisms, which would branch off first and why?

Lancelet (outgroup) Salamander Tuna Turtle Leopard Dolphin oo - Lamprey o - Character (1) Backbone (2) Hinged jaw (3) Four limbs - o - - o - o 0 (4) Amnion (5) Milk o 0 0 0 (6) Dorsal fin 1 *Although adult dolphins have only two obvious limbs (their flippers), as embryos they have two hind-limb buds, for a total of four limbs.

Answer 1

Solution

• The organism Lancelet will branch off first because out of 6 characters used to make phylogenetic tree ,for all characters lancelet shows 0 character status.
• it means total six characters are absent in lancelet and in other organisms presence of one or few or all characters.
• thatswhy other all group are closely related to each other at various degrees.
• but lancelet are distantly related to other groups thatswhy lancelete is considered as outgroup.
• outgroup never share characters which are present in other ingroups.
• hence lancelet brach off first in phylogenetic tree.